POS0128 MICROVASCULAR INVOLVEMENT IN BEHÇET’S DISEASE. STUDY OF NAILFOLD CAPILLAROSCOPY AND ENDOTHELIAL PROGENITOR CELLS IN A NATIONAL REFERRAL CENTER
Authors: B. Atienza-Mateo, A. del Peral Fanjul, V. Pulito-Cueto, D. Prieto-Peña, M. A. González-Gay, R. Blanco
Journal: Annals of the Rheumatic Diseases (2022)

Background Ocular manifestations of Behçet’s disease (BD) are globally recognized and widely studied [1] . Vascular lesions are also frequent but less explored [2] . Microvascular involvement may be clinical (as Raynaud’s phenomenon) or subclinical. Vascular microcirculation is studied with Nailfold Capillaroscopy (NFC) that may show capillary abnormalities such as dilated loops, megacapillaries and microhemorrhages. Endothelial progenitor cells (EPCs) have been implied in the pathogenesis of multiple cardiovascular disorders and vasculitis, including BD and could be used as biomarkers. Objectives To assess the microvascular involvement and EPCs in patients with BD. Methods Observational study of unselected consecutive patients with BD assessed in a national referral center from March to May 2021. All patients fulfilled the 2014 ICBD criteria [2]. They were evaluated sequentially with a scheduled clinic visit after signing an informed consent. The main variables collected were a ) periungual capillaries features (loop diameter, tortuosity, vascular density, microhemorrhages and blood flow), and b ) serum EPCs levels. NFC was performed from the second to fifth fingers of both hands using a 500x magnification digital microscope. The following features were considered abnormal: diffuse enlarged capillaries (≥2 capillaries with a diameter of 20-50 µm in at least 2 different fingers), megacapillaries (&gt;50 µm in diameter), reduced vascular density (&lt;9 capillaries/mm or avascular areas), diffuse microhemorrhages (≥2 hemorrhages in at least 2 different fingers) and granular/slow flow. EPCs were studied in unselected BD patients in whom instant blood samples were available and compared with sex-aged matched healthy controls (HC). EPCs from peripheral venous blood were quantified by direct flow cytometry and characterized by simultaneous expression of cell surface markers of stemness (CD34), immaturity (CD133), endothelial commitment (CD309) and a low expression of the pan-leukocyte marker (CD45). Results From a cohort of 120 patients with BD, 42 were evaluated during the period of the study (Table 1). NFC was performed in the 42 cases, being abnormal in 54.8% of them. The most common findings were capillary loop dilation (45.2%), capillary tortuosity (31%), megacapillaries (21.4%) and microhemorrhages (16.7%) (Table 1). Instant blood samples to study EPCs levels were available in 18 BD patients and 12 HC. The median [IQR] frequency of EPCs levels were higher in BD than in HC (p=0.011) (Figure 1). Table 1. Collected data of 42 patients with Behçet’s disease. Demographic data n (%) Women/Men 19 (45.2)/ 23 (54.8) Age (years), mean ± SD 47.86±12.99 Clinical vascular involvement n (% ) Deep vein thrombosis 4 (9.52) Superficial thrombophlebitis 1 (2.38) Arterial aneurysms 2 (4.76) Acute myocardial infarction 3 (7.14) Arterial thrombosis 1 (2.38) Raynaud’s phenomenon 10 (23.81) Nailfold capillaroscopy Findings n (% ) Abnormal 23 (54.8) Dilated loops (20-50 µm) ≥2 in at least 2 fingers 19 (45.2) Megacapillaries (&gt;50 µm) 9 (21.4) ≥2 in at least 2 fingers 3 (7.1) Capillary tortuosity 13 (31) Microhemorrhages 7 (16.7) ≥2 in at least 2 fingers 1 (2.4) Reduced vascular density 3 (7.1) Granular flow 1 (2.4) Figure 1. Quantification of endothelial progenitor cells population by flow cytometry in 18 patients with Behçet’s disease and 12 healthy controls. Mann-Whitney U test. BD: Behçet’s disease. EPCs: endothelial progenitor cells. HC: healthy controls. Conclusion Microvascular involvement is common in BD and can be easily assessed by NFC. Furthermore, EPCs quantification may be a useful serum biomarker of the disease. References [1]Atienza-Mateo B, et al. Arthritis Rheumatol. 2019 Dec;71(12):2081-2089. doi: 10.1002/art.41026 [2]Emmi G, et al. Intern Emerg Med. 2019 08;14(5):645-52. [3]International Team for the Revision of the International Criteria for Behçet’s Disease (ITR-ICBD). J Eur Acad Dermatol Venereol. 2014 Mar;28(3):338-47. Acknowledgements We acknowledge all the patients who participated in the study. Disclosure of Interests Belén Atienza-Mateo Speakers bureau: Pfizer, Celgene, Novartis, Sanofi, Janssen, UCB, Eli Lilly, Grant/research support from: Abbvie, Roche, Alfonso del Peral Fanjul: None declared, Verónica Pulito-Cueto: None declared, Diana Prieto-Peña Speakers bureau: Pfizer, Celgene, Novartis, Sanofi, Janssen, UCB and Eli Lilly, Grant/research support from: Galapagos, Miguel A González-Gay Speakers bureau: Abbvie, Pfizer, Roche, Sanofi, Eli Lilly, Celgene, MSD, GSK, Grant/research support from: Abbvie, MSD, Jansen, Roche, Ricardo Blanco Speakers bureau: Abbvie, Amgen, Bristol-Myers, Galapagos, Janssen, Lilly, MSD, Novartis, Pfizer, Roche and Sanofi., Grant/research support from: Abbvie, Roche